How to erase a hard drive


In this ‘how to’ I will show you how to erase a hard drive so that all the data is gone and cannot be accessed by anyone else. You would want to do this if you were selling or throwing out the computer.

A lot of people are not tech savvy and don’t understand how data is stored on hard drives. Mind you, there’s nothing wrong with this as most people just want to use the computer to send emails, write letters, play games etc.

However there lack of knowledge could unfortunately lead to sensitive data on a disused hard drive finding its way into someone else’s hands.

When you use a format utility or some other windows program to delete data off the hard drive, you don’t actually you erase the data – you only you erase the  location information for the data. What this means is that the operating system can’t see the data and for most users you would issue that the drive is empty. However the data is still there and all you need is the right utility (which is easily found on the Internet) to find and retrieve that data.

Large companies and government organisations have standards for securely erasing data on hard drives, and generally can be classified into one of the 3 following categories:

1) – Physically destroy the hard drive – as the name suggests this is performing a physical action to stop the hard drive from ever working again eg melting it, drilling multiple holes through the hard drive platters (as my picture above would suggest), shredding or complete disintegration of the drive. There are companies out there that will actually do this for you for a small fee.

2) Degaussing the hard drive – basically this is the process of wiping a huge, very strong magnets over the hard drive to erase the data. Again there are large companies that do this for you.

3) Using free data destruction software (this is what the general consumer would do) –  This special software will overwrite the data on the hard drive many times and and in a certain way, which makes the extraction of any useful data virtually impossible.

The software I use is found is at

Disclaimer: As the website says, there is No guarantee that data is removed using the software, and I also don’t guarantee it but it is the software of choice in the IT community, and that’s a pretty good endorsement that it works well in my eyes.

The process is quite easy, and there are not too many instructions to show you on how to erase a hard drive. Download the image to your computer and burn a CD with the image on it. This program doesn’t run within windows but your computer will boot from the CD that you have just burnt. All you have to do is follow the instructions when the program starts up (below is the splash screen when DBAN starts up):


image source:

Just be aware that this process can take a number of hours depending on the type of you raise your selected. Basically the longer it takes the more thorough the data destruction is.

And there you have it. It’s important to know how to erase a hard drive if you are in the process of throwing out old computers and selling them etc. And you can be fairly sure that the drives will be wiped clean.

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